1. Field of the Invention
A certain aspect of this disclosure relates to a film deposition apparatus and a substrate processing apparatus.
2. Description of the Related Art
In a known method or process for depositing (or forming) a film in a semiconductor manufacturing process, a first reaction gas is caused to be adsorbed on the surface of a substrate such as a semiconductor wafer (hereafter simply referred to as “wafer”) in a vacuum atmosphere, and then a second reaction gas is supplied instead of the first reaction gas to cause reaction between the first and second reaction gases, and thereby form one or more atomic or molecular layers. This cycle is repeated multiple times to stack the layers and thereby form a film on the substrate. This method or process is called atomic layer deposition (ALD) or molecular layer deposition (MLD). For example, U.S. Pat. No. 7,153,542, Japanese Patent No. 3144664, U.S. Pat. No. 6,869,641, and Japanese Laid-Open Patent Publication No. 2007247066 disclose apparatuses that perform a film deposition process as described above.
Such a film deposition process is preferably used, for example, to form a high-dielectric film used as a gate oxide. For example, when forming a silicon dioxide film (SiO2), bis-(tertiary butyl amino)-silane (BTBAS) may be used as the first reaction gas (source gas) and ozone gas may be used as the second reaction gas (oxidizing gas).
In a proposed film deposition apparatus, a film deposition process (or film forming process) is performed on multiple substrates that are arranged on a rotary table, which is provided in a vacuum chamber, in the rotational direction of the rotary table. The proposed film deposition apparatus includes multiple process regions arranged apart from each other in the rotational direction of the rotary table in the vacuum chamber. Different reaction gases are supplied into the process regions, and a film deposition process is performed in the process regions. Separation regions are provided between the process regions arranged in the rotational direction. Separation gas supplying units are provided to supply a separation gas into the separation regions and to thereby separate the atmospheres of the process regions.
During a film deposition process, the separation gas is supplied from the separation gas supplying units. The separation gas spreads on the rotary table in forward and backward rotational directions, and forms separation spaces at the separation regions to prevent the reaction gases from mixing. The reaction gases supplied into the process regions are exhausted from exhaust ports provided in the vacuum chamber together with the spread separation gas. While supplying the reaction gases to the process regions and supplying the separation gas to the separation regions, the rotary table is rotated to repeatedly move the substrates between process regions forward and backward and thereby perform ALD or MLD.
The appropriate size of the separation regions vary depending on the process conditions such as the types of gases used. For example, for a process where a relatively long time is necessary for adsorption of molecules in reaction gases, the size of the separation regions is preferably made smaller than that for a process where a relatively short time is necessary for adsorption of molecules in reaction gases. Also, for a process where a relatively long time is necessary for oxidation, it is preferable to set the length in the rotational direction between a region where an oxidation gas is supplied and a separation region. Also, process regions may be provided to cause three or more gases to react with each other on a wafer, and separation regions may be provided between the process regions. Thus, an appropriate arrangement of process regions and separation regions may vary depending on the process to be performed.
Here, when reaction gases supplied to different process regions mix and react with each other, particles are generated. To prevent the mixture of reaction gases, a film deposition apparatus is preferably configured to control the directions of exhaust flows. Also, exhaust flows in a vacuum chamber need to be changed according to the number of process regions and the arrangement of separation regions. However, it is troublesome to form exhaust ports in a vacuum chamber each time when a different process is performed. The patent documents mentioned above do not point out this problem and do not provide any solution for this problem.